/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/OnlineTournamentInterface.h
A delegate for when a tournament has been joined
typedef TMulticastDelegate_ThreeParams< void, const FUniqueNetIdRef, const [FOnlineTournamentIdRef](API\Plugins\OnlineSubsystem\Interfaces\FOnlineTournamentIdRef), const [FAdditionalMetaDataMap](API\Plugins\OnlineSubsystem\Interfaces\FAdditionalMetaDataMap) & > FOnOnlineTournamentTournamentJoined